Improvement in screw-driver handles



H. WILKINSON.

SCREW-DRIVER HANDLE. No. 190,459. Patented May 8,1877.

WITNESSES: mmwroa;

UNITED STATES PATENT OFFICE.

HENRY WILKINSON, OF COLLINSVILLE, CONNECTICUT.

IMPROVEMENT IN SCREW-DRIVER HANDLES.

Specification forming part of Letters Patent No. 190,459, dated May 8, 1877; application filed March 24, 1877.

View with the handle revolved just one-sixth of an entire rotation from the position shown in Fig. 1. Fig. 3 is an end View.

The knob at the upper end of the handle is made somewhat larger in diameter than is common, and is slabbed or flattened to form three practically equidistant sides, so that the shape in cross-section is substantially triangular, with a rounded surface interposed at each angle.

This simple change gives a marked increase of efficiency.

This handle is mainly intended for large screw-drivers, where the user needs to put forth considerable power. This triangular knob fits naturally to the grasp of the hand, and afi'ords to the user the strongest possible gripe.

That the slabbed sides should be three in number is essential; for, as any one can satisfy himself by trial, three turns of the wrist-the part of the arm above the elbow remaining stationary-make one complete circle, so that a single twist of the wrist just sufiices to shift the grasp from point to point.

Actual trial shows that the soreness of hand incident to continuous use of the common handle is obviated by the shape of handle herein shown and described.

I claim as my improvement- A screw-driver handle having an enlarged and round-ended head, provided with three flattened sides equidistant and equal-spaced,

as shown and described.

HENRY WILKINSON.

Witnesses:

W. E. SIMoNDs, RoBT. F. GAYLORD. 

